【Dart學習】--之Duration相關方法總結

一，概述

• Duration表示從一個時間點到另一個時間點的時間差
• 如果是一個較晚的時間點和一個較早的時間點，Duration可能是負數

二，創建Duration

• 唯一的構造函數創建Duration對象
  

  Duration({int days: 0, int hours: 0, int minutes: 0, int seconds: 0, int milliseconds: 0, int microseconds: 0})

• 可以使用其中的一個或者幾個參數創建
  • 只是用其中的一個參數
    

    Duration ration = Duration(days: 1);
    print(ration); //24:00:00.000000
    Duration ration1 = Duration(hours: 10);
    print(ration1); //10:00:00.000000

  • 只是用其中的兩個參數
    

    Duration ration2 = Duration(days: 1, hours: 3);
    print(ration2); //27:00:00.000000

  • 使用所有的參數
    

    Duration ration3 = Duration(days: 2, hours: 2, minutes: 23, seconds: 34, milliseconds: 56, microseconds: 89);
    print(ration3); //50:23:34.056089

三，相關運算

• 示例
  

  Duration time1 = Duration(days: 1, hours: 1, minutes: 1, seconds: 1, milliseconds: 1, microseconds: 1);
  Duration time2 = Duration(days: 2, hours: 2, minutes: 2, seconds: 2, milliseconds: 2, microseconds: 2);
  print(time1); //25:01:01.001001
  print(time2); //50:02:02.002002

  • 加
    

    print(time1 + time2); //75:03:03.003003

  • 減
    

    print(time1 - time2); //-25:01:01.001001

  • 乘
    

    print(time1 * 2); //50:02:02.002002

  • 除(取整)
    

    print(time2 ~/ 3); //16:40:40.667334

  • 比較
    

    print(time1 > time2); //false
    print(time1 >= time2); //false
    print(time1 == time2); //false
    print(time1 < time2); //true
    print(time1 <= time2); //true

  • 取相反值
    

    print(-time1); //-25:01:01.001001
    print(-(time1 - time2)); //25:01:01.001001

四，相關函數

• 示例
  

  Duration time3 = -Duration(days: 1, hours: 1, minutes: 1, seconds: 1, milliseconds: 1, microseconds: 1);
  print(time3); //-25:01:01.001001

  • 取絕對值
    

    print(time3.abs()); //25:01:01.001001

  • 比較, 返回值, 0: 相等, -1: time1 < time2, 1: time1 > time2
    

    print(time1.compareTo(time2)); //-1

  • 字符串形式
    

    print(time1.toString());